#include <experimental/filesystem>
#include "dbms/dbms.hpp"
#include "durability/snapshooter.hpp"
#include "gtest/gtest.h"

namespace fs = std::experimental::filesystem;

const std::string SNAPSHOTS_FOLDER_ALL_DB = "snapshots_test";
const std::string SNAPSHOTS_TEST_DEFAULT_DB_DIR = "snapshots_test/default";

// Other functionality will be tested in recovery tests.

std::vector<fs::path> GetFilesFromDir(
    const std::string &snapshots_default_db_dir) {
  std::vector<fs::path> files;
  for (auto &file : fs::directory_iterator(snapshots_default_db_dir))
    files.push_back(file.path());
  return files;
}

void CleanDbDir() {
  if (!fs::exists(SNAPSHOTS_TEST_DEFAULT_DB_DIR)) return;
  std::vector<fs::path> files = GetFilesFromDir(SNAPSHOTS_TEST_DEFAULT_DB_DIR);
  for (auto file : files) {
    fs::remove(file);
  }
}

class SnapshotTest : public ::testing::Test {
 protected:
  virtual void TearDown() {
    CleanDbDir();
    CONFIG(config::SNAPSHOT_CYCLE_SEC) = snapshot_cycle_sec_setup_;
  }

  virtual void SetUp() {
    CleanDbDir();
    snapshot_cycle_sec_setup_ = CONFIG(config::SNAPSHOT_CYCLE_SEC);
    CONFIG(config::SNAPSHOT_CYCLE_SEC) = "-1";
  }
  std::string snapshot_cycle_sec_setup_;
};

TEST_F(SnapshotTest, CreateLessThanMaxRetainedSnapshotsTests) {
  const int max_retained_snapshots = 10;
  Dbms dbms;

  for (int i = 0; i < 3; ++i) {
    auto dba = dbms.active();
    Snapshooter snapshooter;
    snapshooter.MakeSnapshot(*dba.get(), SNAPSHOTS_TEST_DEFAULT_DB_DIR,
                             max_retained_snapshots);
  }

  std::vector<fs::path> files = GetFilesFromDir(SNAPSHOTS_TEST_DEFAULT_DB_DIR);
  EXPECT_EQ(files.size(), 3);
}

TEST_F(SnapshotTest, CreateMoreThanMaxRetainedSnapshotsTests) {
  const int max_retained_snapshots = 2;
  Dbms dbms;

  fs::path first_snapshot;
  for (int i = 0; i < 3; ++i) {
    auto dba = dbms.active();
    Snapshooter snapshooter;
    snapshooter.MakeSnapshot(*dba.get(), SNAPSHOTS_TEST_DEFAULT_DB_DIR,
                             max_retained_snapshots);
    if (i == 0) {
      std::vector<fs::path> files_begin =
          GetFilesFromDir(SNAPSHOTS_TEST_DEFAULT_DB_DIR);
      EXPECT_EQ(files_begin.size(), 1);
      first_snapshot = files_begin[0];
    }
  }

  std::vector<fs::path> files_end =
      GetFilesFromDir(SNAPSHOTS_TEST_DEFAULT_DB_DIR);
  EXPECT_EQ(files_end.size(), 2);
  EXPECT_EQ(fs::exists(first_snapshot), false);
}

TEST_F(SnapshotTest, CreateSnapshotWithUnlimitedMaxRetainedSnapshots) {
  const int max_retained_snapshots = -1;
  Dbms dbms;

  for (int i = 0; i < 10; ++i) {
    auto dba = dbms.active();
    Snapshooter snapshooter;
    snapshooter.MakeSnapshot(*dba.get(), SNAPSHOTS_TEST_DEFAULT_DB_DIR,
                             max_retained_snapshots);
  }

  std::vector<fs::path> files = GetFilesFromDir(SNAPSHOTS_TEST_DEFAULT_DB_DIR);
  EXPECT_EQ(files.size(), 10);
}

int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}